Nonreciprocal quantum transport of ultracold atoms in a driven quadruple-well potential with synthetic gauge fields

Abstract By introducing two opposing driving fields with a reduced electric field strength, we successfully achieve quantum non-reciprocal transport of ultracold atoms confined within a quadruple-well system that incorporates a synthetic gauge field. This achievement not only disrupts the inherent robustness of reciprocal transport in such systems but also underscores the indispensability of coherent drives in facilitating quantum non-reciprocal transport, irrespective of the presence or absence of dissipation. In the absence of dissipation, the interplay between the synthetic gauge field and the driving fields endows the system with the capacity for non-reciprocal transport of ultracold atoms. This finding highlights the significance of unequal reduced field strengths in the genesis of nonreciprocal quantum transport, with the synergistic effects of the synthetic gauge field and coherent drives dictating both the magnitude and direction of the nonreciprocal transport. In the presence of dissipation, although the population and tunneling probability of ultracold atoms are diminished, the non-reciprocity of the system can be amplified by the driving fields and the artificial gauge field. This amplification results in an enhancement of non-reciprocity, allowing for the generation of strong unidirectional non-reciprocal windows through the modulation of the combined effects of dissipation, coherent drives, and the synthetic gauge field. Our findings provide a valuable reference for the development of quantum non-reciprocal routers within ultracold atoms, offering insights into the control and manipulation of quantum transport phenomena.